<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		
		<script type="text/javascript">
			function fun(n,o){
				console.log(o)
				return {
					fun:function(m){
						return fun(m,n);
					}
				};
			}
			var a = fun(0); a.fun(1); a.fun(2); a.fun(3);
			var b = fun(0).fun(1).fun(2).fun(3);
			var c = fun(0).fun(1); c.fun(2); c.fun(3);
		</script>
	</body>
</html>
